2 X M.2 Sockets - Wich one for OS?

Hi!

I recently made a system configuration with:

- ASRock X470 Master SLI motherboard, wich has 1 x Ultra M.2 Socket and 1 x M.2 Socket

- 1 x SSD M.2 Intel 660p Series 512GB

- 1 x SSD M.2 HP EX900 250GB

My purpose was to install the HP EX900 SSD (wich is faster: 2100 MB/s read and 1300 MB/s write) in the Ultra M.2 Socket, as a system drive.

And the Intel 660p SSD was going to be installed in the M.2 Socket to run as a work drive for Premiere - projects 'm working on and Premiere's cache files.

Now i have second thoughts... should i change them between each other?

I mean system SSD on M.2 Socket, and work SSD on Ultra M.2 Socket?

How is better?